Hydraulic cushioning device for railway vehicles



Nov. 12, 1968 w. H. PETERSON HYDRAULIC CUSHIONING DEVICE FOR RAILWAY VEHICLES Fil edMay V11, 1967 2 SheetsSheet 1 If RN ,x m0 T N5 T 1 R Wm /1 E P. V

m L n W V! B Nov. 12, 1968 w. H. PETERSON HYDRAULIC CUSHIONING DEVICE FOR RAILWAY VEHICLES 2 Sheets-Sheet 2 INVE'NTOR WILLIAM H. FZERSON /QQQOZfl TT'Y.

United States Patent 3,416,416 HYDRAULIC CUSHIONING DEVICE FOR RAILWAY VEHICLES William H. Peterson, Homewood, Ill., assignor to Pullman Incorporated, Chicago, III., a corporation of Delaware Filed May 11, 1967, Ser. No. 637,738 8 Claims. (Cl. 21343) ABSTRACT OF THE DISCLOSURE A hydraulic fluid extensible cushioning device having a pair of concentric cylinders connected together with one of said cylinders including a low pressure reservoir and a first bore in which a piston member is slidable, the piston member including a tubular elonagted piston rod slidable relative to the second cylinder and including a rolling seal connected to the second cylinder adjacent the piston member and having an end portion connected to the tubular piston rod, the said rolling seal being substantially coextensive with the bore provided between the second cylinder and the tubular piston rod, and including an expansible chamber within said tubular piston rod having supported therein coextensive with the length of said chamber an accumulator bag having a gas under pressure therein, the end of said accumulator bag having a portion thereof received in a concave recess of said piston member and being disposed relative to the piston membel so as to be compressed during movement of the piston member to its contracted position, said accumulator bag during the contracted position serving to provide means to return the piston member and rod to its extended position.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to the art of cushioning devices used in the cushioning of railway vehicles to protect the lading and goods carried therein as well as the car from overspeed impacts resulting during car coupling operations. Cushions of this type must be of simplified construction, able to withstand constant usage, the severe elements, and the rough handling to which railway cars normallyare subjected. Cushions of this type must provide a minimum of maintenance and particularly must have a sealing arrangement which will not leak despite adverse weather and operating conditions and must have a foolproof returndevice to move the piston member and rod from a contracted to an extended position.

(2) Description of the prior art Railroad cushions of the prior art have generally included spring return devices adapted to return the piston rod and piston from a contracted to an extended position. Certain cushions have included stationary seals between the piston rod and hydraulic cylinder which in many instances have been unsatisfactory because of frequent hydraulic fluid leakage problems. Units of this type may also have included gas-filled chambers with a floating piston adapted and arranged to return the piston rod and member to its original extended position. Stationary seals of the type utilized in the prior art have, due largely to weather conditions and rough usage, become -worn and damaged thus in effect causing frequent maintenance due to fluid leakage. The present invention proposes to solve the problems in the aforementioned prior art devices in that an improved expansible chamber type of cushion is provided having an improved return means and a particular relationship of parts combined with each other to provide an improved cushion device.

Patented Nov. 12, 1968 SUMMARY The cushioning device disclosed herein is of the expansible chamber type in that the piston member and rod is provided with a relatively large chamber in which an accumulator bag is disposed. The accumulator bag has its end portion, which is initially subjected to the fluid pressures, disposed in a relative protected position within a cavity of the piston member and in a position to receive indirectly the high pressure flow which enters through passage means in the piston member from the high pressure side of the cushion so as to efiectively compress the gas contained within the accumulator bag and provide a positive return action of the unit from its contracted to its extended position. Further, the cushion unit includes improved elements of design including a check valve in the piston member operative during the return stroke from the contracted position so as to expedite the discharge of fluid from the expansible chamber to the high pressure side of the piston member and to a suitable reservoir. Further, the device comprises a first and second cylinder connected together to pro-vide a high pressure chamber and also an extended annular receiving space between the second cylinder and the piston rod which is of substantially the same circumference of diameter of said piston member and said annular space ha ving therein a rolling type seal extending the length of said annular space to eiiectively seal the cushion against leakage under all operating conditions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an improved bydraulic cushioning device showing the said device in an extended position;

FIG. 2 is a cross-sectional view similar to FIG. 1 showing the hydraulic cushioning device in a contracted position;

FIG. 3 is an enlarged cross-sectional view taken substantially along the line 33 of FIG. 1

FIG. 4 is an enlarged cross-sectional view through the piston member and cylinder taken substantially along the line 4-4 of FIG. 1;

FIG. 5 is an enlarged cross-sectional view through the piston rod and a cylinder portion taken substantially along the line 55 of FIG. 1; and

FIG. 6 is an enlarged cross-sectional view taken through the end of a cylinder and reservoir substantially along line 66 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT 12 by means of a weld 13 which provides an end closure for a first bore 14. The bore 14 is provided with a plurality of longitudinally spaced metering openings 15 which provide for communication between the bore 14 and a pair of reservoirs designated at 16 as best shown in FIG. 3. Each reservoir 16 is formed by means of an angle 17 securely welded as indicated at 18 to the outer peripheral surface of the first cylinder 11. As shown in FIG. 1 one end of each reservoir 16 is closed by means of a wall 19, the other end of each reservoir 16 being closed by means of a wall 20 as shown in FIG. 6. Fluid. filler openings are designated at 21 which are suitably capped by means of closure plugs 21'.

The cushioning device 10 also comprises a second cylinder 22 concentric with the first cylinder 11. The second cylinder 22 is provided at one end with a closure plate and guide member 23 having a guide opening 24. A stationary seal 25 is suitably retained in the guide member 23. The closure plate and guide member 23 is suitably rigidly connected to the second cylinder 22 by means of a weld 26.

The first cylinder 11 is rigidly connected to a collar 27 by means of a weld 28. As best shown in FIG. 4 the collar 27 includes a plurality of threaded openings 29, and as shown in FIG. 1, is provided with an annular undercut 30. The second cylinder 22 includes a longitudinally extending second bore 31 and is provided at its end adjacent to said collar 27 with a plurality of cars 32 as best shown in FIG. 5. The ears 32 are provided with openings 33 which contain bolts 34 screwed in the openings 29 to securely connect the second cylinder 22 to the collar 27.

As best shown in FIGS. 1 and 3 a piston member is designated at 35 and includes a skirt 36 provided with an annular undercut portion 37. A tubular piston rod 38 is provided with a threaded end 39 in secure engagement with the threaded undercut 37 for connecting the rod 38 to the piston member 35. The piston member 35 is also provided with an enlarged recess 40 in communication with a plurality of radially extending passages 41. The first cylinder 11 is provided at its end adjacent to the collar 27 as best shown in FIGS. 1 and 3 with a pair of openings 42 which provide for communication between the reservoirs 16 and the passages 41. The piston mem ber 35 is provided on its outer face With a dished recess 43 terminating in an annular shoulder 44 provided with a plurality of radially extending passages 45 which communicate with an annular recess 46 in the face of the piston 35. A snap ring 47 is provided in the recess 46 behind which a check valve plate 48 is disposed. A connecting bore 49 communicates with the recess 46 and provides therewith an annular shoulder portion 46, the said connecting bore 49 communicating with the enlarged recess 40. The letter A as indicated in FIG. 1 is directed to the high pressure side of the piston 35 and the letter B is directed to the low pressure side of the piston 35. A bearing ring 50 of plastic or similar material is disposed in a circumferential recess 51 of the peripheral surface of the piston 35 and is raised with respect thereto for engaging in sliding relation the bore 14 during movement of the piston 35.

The tubular piston rod 38 is provided with an expansible chamber 52 best indicated in FIGS. 1 and 2. The expansible chamber 52 is closed at one end by means of a base plate 53 having a reduced serrated annular projection 54 and an annular shoulder 55 having seated in its circumferential surface a sealing ring 56. An annular connecting element 57 extends about the periphery of the tubular piston rod 38 and is retained thereon by means of a snap ring 58 connected to the piston rod 38. The plate 53 is connected to the connector element 57 by means of a plurality of bolts engaging threaded openings (not shown) similar to the connection of cylinder 22 to the collar 27 as aforementioned. The plate 53 also is provided with a charging bore or passage 59 having a suitable inflating valve 60 contained therein which communicates with a threaded bore 61' for filling with a suitable gas an accumulator bag 61 disposed within the expansible chamber 52. The accumulator bag 61 may be filled with air or any suitable inert gas to a pressure which will permit the gas to remain above its liquification .point during all operating conditions. The accumulator bag 61 is provided with a domed end portion 62 which projects into a concavity 62' formed in the skirt 36 as best shown in FIGS. 1 and 2. An open end of the accumulator bag 61 is indicated at 63 the said end being rigidly secured about the serrated surface of the reduced portion 54 by means of a split band 64 connected together by means of a screw 65 as best indicated in FIG. 1.

The tubular piston rod 38 is substantially of the same outer diameter as the piston 35 and is spaced from the second bore 31 of the second cylinder 22 by means of an annular space 66 extending substantially the length of the cylinder 22. A rolling seal 67 is disposed in the space 66 and includes at one end a reversely turned end portion 68 provided with a ring-shaped portion 69 extending about the circumference of the piston rod 38 and being connected thereto by means of a first collar 70 welded to the rod 38 and tightly engaging the ring-shaped portion 69 against a second collar 71 held in position by means of a snap ring 72 recessed in the piston rod 38. The other end of the rolling seal 67 is rigidly supported in the area of the piston 35 when in an extended position. A collar 74 is welded to the bore 31 and tightly clamps the ringshaped portion 73 against a shoulder 75 on the collar 27, the said clamping engagement arising from the tightening of the threaded bolts 34.

THE OPERATION The cushioning unit 10 herein described may be utilized in the cushioning of rail cars and in the environment particularly disclosed in the Peterson Patent 3,003,436, patented Oct. 10, 1961. The position of the cushioning device shown in FIG. 1 is termed the extended position and as shown in FIG. 2 the device during a certain speed of imp-act may be moved to a completely closed or contracted position. Upon contraction, the piston 35 is moved in the direction toward the base plate 12 and fluid within the first bore 14 and on the high pressure side A is forced through the metering openings 15 into the reservoirs 16. The metering openings 15 are disposed to provide for a predetermined constant force travel as specifically set forth in the aforementioned patent though the present invention, of course, is not limited thereby. As the piston member 35 is moving to the contracted position the valve plate 48 is seated against the shoulder 46 in the recess 46 and the bores 45 are closed with respect to the bore 49 and expansible chamber 52. Fluid from the reservoirs 16 flows through the passages 42 into the passages 41 while simultaneously fluid flow enters into the space 66 since the skirt 36 of the piston member 35 is of a lesser diameter than the internal diameter of the collar 27. The location of the passages 41 is such that the surge of fluid into the space 40 prevents the direct impingement of the fluid against the domed end portion 62 of the accumulator bag 61. Upon complete contraction of the device, the accumulator bag 61 assumes a position similar to that shown in FIG. 2 with the gas therein under increased compression. The fluid in the annular space 66 is effectively retained therein by virtue of the novel connection of the rings 69 and 73 which prevents leakage from the device. By virtue of the inner diameter of the first bore 14 and its relation to the piston head skirt 36 an uninterrupted flow of fluid may flow to the space 66 which is substantially continuous with the length of the second cylinder 22 as shown in FIG. 2. The accumulator bag 61 is positioned to avoid the direct force of the jet stream entering through the passages 41 since the recess 40 provides a converging point and a unitary pressure is applied to the domed portion 62 of the accumulator bag 61. The relation of the piston member 35 to the bore 14 is such that the ring 50 provides an effective barrier against fluid leakage at its bearing point and the sealing fit or tolerance of the seal 25 is not critical in that the rolling seal 31 provides the required seal to prevent the escape of the fluid from the device.

After the device has been moved to the contracted position shown in FIG. 2 and the coupling impact of the railroad car has terminated, the pressure of the gas within the accumulator bag 61 provides for expansion of the bag in the expansible chamber 52 whereupon fluid flows in an opposite direction from the high pressure side B to the low pressure side A by means of the passages 41 and openings 42 directly into the reservoirs 16 and into the bore 14. In order for the device to return to its extended position as quickly as possible the check valve 48 is provided. Upon the return stroke of the piston rod 38 the piston member 35 moves to the right in FIG. 1 and fluid entering into the bore 49 and recess 46 forces the valve plate 48 against the snap ring 47 permitting fluid flow through the bores 45 into the first bore 14. This rapid return of the device to its extended position is desirable so as to position the unit in a manner where it is quickly capable of absorbing any additional impacts. It is thus seen that the improved cushion device provides an effective arrangement for the return of the unit to its extended position with effective sealing means and passage arrangements designed to provide for a minimum of maintenance under all operating conditions. The disposition of the accumulator bag relative to the skirt and the concavity 62 provides an effective arrangement designed to guarantee the life of the accumulator bag 61 despite the most severe operating conditions.

I claim:

1. A hydraulic cushioning device for use in railway vehicles comprising:

a first cylinder having a first bore,

a first base plate fixed to one end of said first cylinder,

said first bore including a plurality of longitudinally spaced metering openings, a reservoir connected to said first cylinder communicating with said metering openings,

a piston member reciprocable within said first bore and having an annular recess including a check valve, said piston member defining a high pressure side facing said first base plate and a low pressure side on the opposite side thereof,

a second cylinder connected to said first cylinder and concentric therewith,

said second cylinder having a second bore,

a closure and guide member having a guide opening connected to said second cylinder at one end thereof,

a tubular piston rod connected to said piston member and projecting outwardly through said guide opening,

said tubular piston rod having a second base plate connected thereto at one end thereof to provide therein an expansible chamber,

an elastic accumulator bag disposed in said expansible chamber and being substantially coextensive with said second cylinder,

said cylinder rod having an outer circumferential surface spaced from said second cylinder to provide an annular space substantially coextensive with said second cylinder,

0. flexbile annular tubular shaped seal having an open end ring-shaped portion rigidly fixed to an end of the second cylinder adjacent to said piston member in an extended position,

said seal having a closed ring-shaped reversely turned end portion fixedly connected to said circumferential surface adjacent to said closure and guide member,

said first cylinder bore having an opening means providing for communication between said first bore and said second bore on said low pressure side positioned to provide for communication between said low pressure side and with said reservoir whereby movement of said piston toward said first base plate to a contracted position provides for the flow of hydraulic liquid from said high pressure side of said piston to said reservoir to said low pressure side into said expansible chamber and into said annular space between said circumferential surface and said tubular seal.

2. A hydraulic cushioning device for use in railway vehicles comprising:

a first cylinder having a first bore,

a first base plate fixed to one end of said first cylinder,

a piston member reciprocable within said first bore and having an annular recess including a check valve, said piston member defining a high pressure side facing said first base plate and low pressure side on the opposite side thereof,

a second cylinder connected to said first cylinder and concentric therewith,

said second cylinder having a second bore,

a closure and guide member having a guide opening connected to said second cylinder at one end thereof,

a tubular piston rod connected to said piston member and projecting outwardly through said guide opening,

said tubular piston rod having a second base plate connected thereto at one end thereof to provide therein an expansible chamber,

an elastic accumulator bag disposed in said expansible chamber, being substantially coextensive therewith and including a closed end portion located adjacent said piston member,

means supporting an opposite end of said accumulator bag on said piston rod adjacent said second base plate,

said cylinder rod having an outer circumferential surface spaced from said second bore to provide an annular space substantially co-extensive with said second cylinder,

a flexible tubular shaped seal disposed in said annular space, said seal having an open end ring-shaped portion rigidly fixed to an end of the second cylinder adjacent to said piston member when in an extended position,

said seal having a closed ring-shaped reversely turned end portion fixedly connected to said circumferential surface adjacent to said closure and guide member,

means on said first cylinder providing communication between said first and second bores, whereby movement of said piston member toward said first base plate to a contracted position provides for the tfiOW of hydraulic liquid from said high pressure side of said piston to said low pressure side into said expansible chamber and into said annular space between said circumferential surface and said tubular seal.

3. The invention according to claim 2, and

said piston member including passage means opening outwardly of said high pressure side and communicating with said annular recess, said annular recess providing fiuid communication from said expansible chamber to said first bore, during movement of said piston to the extended position and said check valve blocking communication of fiuid through said passage means during movement of said piston member to said contracted position.

4. The invention according to claim 2, and

said piston member including passage means, said annular recess and said passage means communicating with each other and opening on said high pressure side,

an enlarged annular recess in said piston member opening on said low pressure side,

a reduced diameter passage connecting said recesses and providing in said first recess an annular shoulder, said check valve being longitudinally movable in said first recess against said shoulder during movement of said piston member to said contracted position, and a plurality of radially extending passages in said piston member, said radially extending passages communicating with said enlarged annular recess and said means on said first cylinder providing communication between said first and second bores.

5. A hydraulic cushioning device for use in railway vehicles comprising:

a first cylinder having a first bore,

a first base plate fixed to one end of said first cylinder,

a piston member reciprocable within said first bore said piston member defining a high pressure side facing said first base plate and a low pressure side on the opposite side thereof,

a second cylinder connected to said first cylinder and concentric therewith,

said second cylinder having a second bore,

a closure and guide member having a guide opening connected to said second cylinder at one end thereof,

a tubular piston rod connected to said piston member and projecting outwardly through said guide opening,

said tubular piston rod having a second base plate connected thereto at one end thereof to provide therein an expansible chamber,

an elastic accumulator bag disposed in said expansible chamber, being substantially coextensive therewith and including a closed end portion located adjacent said piston member,

means supporting an opposite end of said accumulator bag on said piston rod adjacent said second base plate,

said piston rod having an outer circumferential surface spaced from said second bore to provide an annular space substantially coextensive with said second cylinder,

8. flexible tubular shaped seal disposed in said annular space, said seal having an open end fixed to an end of the second cylinder adjacent to said piston member when in an extended position,

said seal having a closed end portion fixedly connected to said circumferential surface adjacent to said closure and guide member,

means providing communication between said first and second bores whereby movement of said piston member toward said first base plate to a contracted position provides for the flow of hydraulic liquid from said high pressure side of said piston to said low pressure side into said expansible chamber and into said annular space between said circumferential surface and said tubular seal.

6. The invention according to claim 5,

said piston member having a skirt portion,

an enlarged recess in said skirt portion opening into said expan-sible chamber,

a plurality of radially extending passages in said piston member communicating with said enlarged recess and said means providing communication between said first and second bores,

and a concavity formed in said skirt communicating with said enlarged recess,

said closed end portion of said bag being received in said concavity during the extended position of said piston member.

7. The invention according to claim 6,

wherein the outer diameters of said piston rod circumferential surface and said skirt are substantially the same,

said piston member including an outer peripheral surface havin guide means circumferentially extending with said peripheral surface and being elevated with respect thereto, and

said guide means engaging in sliding relation said first bore.

8. The invention in accordance with claim 6,

said communicating means on said first cylinder and said annular space being longitudinally aligned to provide an uninterrupted flow of fluid to said annular space during movement of said piston member.

References Cited UNITED STATES PATENTS 2,841,294 7/1958 Hendrikson et al 21343 3,139,193 6/1964 May 213-43 3,330,422 7/1967 Rasmussen 213-43 35 DRAYTON E. HOFFMAN, Primary Examiner. 

